Wednesday, 4 January 2017

First Year of my PhD: Generating a better understanding of the UK’s shale gas...by Patrick Whitelaw

Shale samples from our core store.

The shale industry is rapidly changing, with large developments such as the first fracking licenses being awarded since I started my research. However still relatively little is known about the UK’s shale gas potential and how much focus should be placed the industry’s development. With the research I am currently undertaking aiming to help shape and direct the government’s legislation on a controversial industry.

Initially my PhD started with a wide range of training, learning to use the machinery and conduct the experiments that will form the core of the next four years. These include hydrous pyrolysis where shale samples are heated up under intense pressures to simulate subsurface conditions. High pressure methane adsorption, to understand the potential of shale to adsorb methane, and consequently how much methane can be extracted from it and surface area and porosity measurements to calculate the pore volumes of shales which when correlated with methane adsorption can provide information about their gas holding potential. Determining the maturity of the shale (how far along the gas production lifeline they are) with vitrinite reflectance has been ongoing, as this is a skill that takes years to master.

High pressure volumetric analyser for high pressure
methane isotherms.

I have continued work on immature Rempstone shale samples from the midlands which have not yet produced oil and gas. Using hydrous pyrolysis sequential experiments, the amount of gas generated by these samples over a lifetime of subsurface conditions has been calculated, and using data from the high pressure methane adsorption experiments, which correlate well with the pyrolysis, a much better estimate of the amount of methane these shales are able to produce has been formed. Currently this data is getting written up for publication, hopefully in a high impact journal.

Using the method developed on the Rempstone samples, I am aiming to see similar results with different shales from northern England near in Lancashire, the area where the fracking licences have been awarded. Initial sampling of two shales from the Grange Hill and Preese Hall (the first prospective shale well drilled in the UK) wells was carried out with samples from a wide variety of depths taken from BGS core stores. Unfortunately many of these samples contained high levels of pyrite preventing many forms analysis. The pyrite prevents vitrinite reflectance as it is too bright, as well as causing the samples to be unsafe when heated up to high temperatures as the formation of sulphur dioxide can cause an dangerous explosion. New samples were however collected either handpicked Grange Hill samples that contain low levels of pyrite or samples from a new Becconsall well. Initial testing has been carried out on the samples and selection for and development of hydrous pyrolysis experiments has begun.

In February I will be presenting for the first time at the Geological Society Conference in London. This should provide a great opportunity to meet people in both academia and corporate environments who have similar interest in the field, as well as showing off our results which have been very promising up to this point. Hopefully by this time as well the paper detailing our results will be finished and on its way to being published in a high impact journal.

High temperature hydrous pyrolysis experiment.

After the return of the Christmas break I will begin my maturation experiments of the samples collected from the Becconsall and Grange Hill wells using the shallower samples with a series of hydrous pyrolysis experiments. Once experimental maturation is completed I will then compare how well this mimics the natural maturation of these shales, by comparison with the deeper cores. This should show how accurate the experimental maturation process is as and if any adjustments need to be made, while also providing gas production data for these cores.